If $ENV{'SystemRoot'} is undefined (by a local %ENV or local $ENV{'SystemRoot'}, perl crashes.

CPAN will occasionally fail to move the directory that a distribution is temporarily unpacked to. (RT#55924)

The 64-bit version does not contain all of the modules that the 32-bit version does. Strawberry Perl is waiting on updates to those modules, as the policy of Strawberry Perl maintainers is not to patch any CPAN modules themselves, but to report required patches to the module author for inclusion in the next version.Known issues are Math::Pari (RT#52146), Win32::API (RT#42685), Crypt::IDEA (RT#55158), Crypt::Blowfish (RT#55173), and Crypt::SSLeay (RT#52408).

There are other modules that are not included with Strawberry Perl that will also have problems with compiling in the 64-bit version that will compile in the 32-bit version. Please report any such problems to the module's author(s), and let us know as well. Tk is a known problem as of this writing, as is Devel::Caller, while a development version of Wx (0.9701_01) must be specified.

The version of 'ppm' released with 5.12.0.0 does not include repositories that support 5.12. (RT#57197) It also tries to install the HTML files, and they are not supposed to install on Strawberry Perl. (RT#43243) These bugs can both be fixed by running the command cpanp install http://strawberryperl.com/package/csjewell/PPM-0.01_03.tar.gz in a command prompt.

PAR::Packer does not work with this version of Perl due to a mismatch between the .dll and .a names for Perl. (RT#57205) 5.12.0.1 will be released soon to fix this.